Year Percent change (Units) 2004 2.014 2005 3.489 2006 5.260 2007 2.627 2008 14.669 2009 0.480 2010 1.770 2011 5.352 2012 4.340 2013 1.851 2014 1.098 2015 -2.237 2016 -1.507 2017 0.050 2018 0.802 2019 -0.110 2020 -0.658 2021 2.247 2022 3.234 2023 6.753 2024 4.250 2025 2.296 2026 2.000 2027 2.000 2028 2.000 2029 2.000